Impregnating or coating of porous articles



Patented Ma '16, 1933 UNITED STATES PAUL KLEIN, runners oABoR AND LAszLo .xAUN-I'rz; 0F BUDAPEST, HUNGABiY,

PATENT oFF c ASSIGNORS TO AMERICAN ANODE 'INC OF AKRON, OHIO IMPREGNATIN'G 0R COATING OF POROUS ARTICLES No Drawing. Application filed January 31, 1928, Serial No. 250,950, and in Germany July 21, 1927.

This invention relates to a method of producing rubber and other goods with textile insertions attached thereto or embedded therein.

In the production of textilegoods provided on one or both sides with a rubber coating, it was the practice to apply to the textile base on one or both sides a rubber-benzine plastic and thereupon to dry and vulcanize the product. It has of late also been proposed to produce such coatings directly from aqueous rubber or the like dispersions by electrophoretic means by passing the material around a conducting drum serving as electrode, immersed in the dispersion, the current strength, composition of the dispersion and speed of the drum or the duration of immersion of the material being adjusted according to the desired thickness and quality of the coating.

It is also possible to effect the coating by causing coagulating ions to enter the rubber dispersion from the liquid-permeable deposition base, for example by imbibing the deposition base with a coagulating liquid. It is moreover known, to provide the material prior to impregnation or coating with various preparations known per se, for the purpose of controlling the degree of penetration into the material of the precipitate produced by electrophoresis.

In the majority of these methods either the adhesion or the quality of the coating, or the thickness of same is nnsatisfactor In most cases the methods were suitable only for coating endless or band-like material. Composite materials consisting of a plurality of caoutchou'c layers and cannot be produced at all or only of imperfect qualit The invention enables such goods to be produced in a perfect quality and consists essentially in that the fibrous materials, fabrics and the like to be impregnated or to be coated by agglomeration from its aqueous dispersion of the substance to be applied, are wetted with an aqueous dispersion of an organic substance which is allied to the substance to be agglomerated prior 'to their immersion into the dispersion in which the textile insertions coating or impregnation is to be efl'ected. Said agglomeration of the substance to be applied may in particular be effected by a migration of ions through the base, mainly from a pure vulcanized or unvulcanized natural latex or from a'vulcanized or unvulcanized natural latex to which has been added additional substance-such as vulcanizing agents, accelerators, dyes, pigments, fillers and the likeor form any aqueous dispersion of caoutchouc, gutta percha, balata or reclaimed rubber or other organic substance such as for example casein or artificial resin.

In most cases it is possible to effect the wetting by means of the same dispersion as that subsequently employed for impregnating by agglomeration. In many cases, however, in order to produce certain effects, it is possible to employ for the wetting dispersions of other substances which adheres both to the base and to the precipitate to be formed.

By the wetting of the material to be coated, in accordance with the invention, the adhesion of the agglomerate produced is increased to an exceedingly high degree. In order to obtain this action it is suflicient for example in the case of thick fabrics and the like, to wet the same superficially with a suitable dispersion of the material to be coated. In cases where a specially high adhesion or complete impregnation is desired, itis advisable to completely imbibe the article with the dispersions in question prior to agglomeration.

The preliminary treatment of the textile goods in accordance with the invention, moreover ensures a completely reliable adhesion to the textile goods of fresh agglomerate skins produced from aqueous dispersions in any desired anner. Thus for example a more or less thick rubber precipitate can be produced from an aqueous rubber dispersion upon any desired base in any manner known per se for example by electroporetic means or by the employment of-dipping moulds which act tated layer an tion may be a plied to the freshly precipithereupon the agglomeration of additional dispersed substance may be continued within or upon the textile material. Either the same or other dispersions or materials may be employed for the aforesaid additional agglomeration as are employed for the production of the first layer.

For example it is possible in an electrophoretic apparatus first to cover the precipitating basewhich may for example be of metal-with an agglomerated layer of rubber in a known manner and thereupon to apply the textile material which has been imbided with rubber latex to said agglomerated rubber layer and the electrophoretic precipitation may be continued in the same apparatus, so that the agglomerate will deposit withln the interior of the textile material and after a prolonged continuation of the 0 eration, 1t will also deposit on the outside 0 the textile material.

It is also possible to carry out the process by immersing for example a dipping mould imbibed with coagulating materials, in an aqueous dispersion of reclaimed rubber thereby covering same with a skin of reclaim. A textile product imbibed with an aqueous dispersion of semi-vulcanized rubber is then applied to the mould and whereupon the mould is immersed for example in ordinary rubber latex. Inasmuch as the fresh reclaimed layer first produced on the mould as well as the rubber latex filling up the hollow spaces of the articles, are permeable to the agglomerating ions, derived from the mould, the outside of the material will be soon coated with a layer of rubber, the thickness of which will depend on the concentration, of the dispersion, the degree of effectiveness of the agglomerating agent derived from the mould and the duration.

A further embodiment of the invention may consist in combining for example a layer of precipitate with a textile band imbibed according to the invention in an electrophoretic apparatus according to the first example, and thereupon passing the band together with the adherent electrophoretic precipitate into a second electrophoretic apparatus, in which the side of the band which was previously facing the outside is covered with a precipitate of the same kind or of a different kind, or that the side of the band which was turned towards the inside in the first apparatus and covered with the precipitate first produced, is turned towards the outside and coated with the new layer of the same or different composition. This example already shows sufficiently the various possible ways of carrying out the present method.

It is self understood that the individual layers may be partially dehydrated or dried prior to or during their union with the further layer, in a manner known per se. However care must be taken to ensure that, prior to the finishing of the product, the drying is not carried out to such an extent that the passage of the ions effecting the precipitation ishindered by the already formed layers.

The invention also enables caoutchouc goods to be produced containing several textile hitherto only be produced in a sutliciently reliable quality by building up the individual unvulcanized constituents and by finishing in the vulcanizing press.

According to the invention an insertion which is wetted or imbibed can always be applied in a reliable manner to the fresh or not quite dry precipitating layer, so that it is an easy matter to provide one or both sides of a textile product coated with a fresh rubber precipitate, with further textile surfaces and to saturate or coat these further with precipitating layers, upon which further textile layers can again be applied in a similar manner.

It is obvious that the method can be carried out in a continuous manner-for example when producing endless goods-as well as intermittently.

The application of valve patches to the inner tubes of pneumatic tyres may be mentioned as an example of an intermittent operation.

A precipitation base of for example zinc, corresponding in shape to the valve patch is covered in a manner known per se with the electrophoretically agglomerated. rubber layer. It is thereupon removed from the dispersion and if desired partially dried. Thereupon a fabric ring wetted with rubber latex is applied to the still moist precipitate and the mould is again immersed in the dispersion in which the precipitation is continued. When the precipitated second rubber layer has attained the requisite thickness, the mould is removed from the bath and an elliptical piece of fabric is applied to the fresh layer if dried; thereupon the mould is immersed again into the dispersion and the second textile layer is covered with a third precipitating layer. Inasmuch as the edges of the finished piece decrease in thickness, it is advantageous to control the thickness at these places by the employment of suitable screens.

In this manner it is possible t coat or impregnate not only fibrous materials proper, such as paper, textile materials and the like but also any other permeable porous and the like materials.

Having now particularly described and ascertained the nature of our said invention and in what manner the same is to be performed, we declare that what we claim is 2- 1. The method of rubberizing fibrous sheet material which comprises preliminarily applying an aqueous dispersion of rubber to insertions which as is well known, could desired after it has been partially the fibers com osing the sheet without substantial coagu ation of the dispersion, then coagulating the rubber of the dispersion applied to the fibers composing the sheet, and simultaneously electrophoretically coatin the sheet with rubber in continuation of, an integral with, that coagulated on the fibers.

2. A process for impregnating and coatin fabric with rubber which comprises preliminarily appl ing an aqueous dispersion of rubber to the fi ers composing the fabric without substantial coagulation of the dispersion, then placing the fabric in contact with a deposition base immersed in an aqueous dispersion of rubber, and coagulating the rubber of the dispersion applied to the fibers composing the fabric, and simultaneousl coagulating a coating of rubber on the fabric in continuaion of, and integral with, the rubber coa ulated on the fibers, by diffusion of coagulating ions from the deposition base.

In testimony whereof we aflix our signatures.

- PAUL KLEIN.

FRANCIS GABoR.

LASZLO KAUNITZ. 

